Compound valve.



B. T. WILLISTON. GOMPOUND VALVE,

APPLloATIoN rILBD MAR.2,1Q14,

1,119,38LI Patented Dec.1,191f

2 SHEETS-SHEET 1.

B. T. WILLISTON.

COMPOUND VALVE.

APPLICATION FILED MALZ, 1914.

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'riv'r onirica BELVIN T. WILLISTON, 0F SOMERVILLE, MASSACHUSETTS, ASSIGNOR T0 THE UNITED INJECTOR COMPANY, OF NEW YORK, N. Y., A CORPORATION 0F NEW YORK.

COMPOUND VALVE.

Specication of Letters Patent.

Patented Dec. 1, 1914.

Application filed March 2, 1914, Serial No. 821,938.

T 0 all whom 'it may concern Be it known that I, BELVIN T. ViLLisron, citizen of the United States, and resident of Somerville, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Compound Valves, of which the following is a specification.

My invention consists in a new and improved compound valve, adapted to seat accurately and effectively over two ports which are Xed with relation to each other, except for variations due to expansion of the metal body in which such ports are formed. Heretofore the generally accepted mode of closing two such ports by a single valve structure has been to make one or both of the valves as a piston valve; usually one valve member has been a seating valve and the other a piston valve.

One of my objects is to provide a valve with two members, both of which close by seating, which will eectively close two relatively lixed ports, in spite of inequalities produced by thermal expansion, and wear.

My improved valve is intended especially for boiler feeding injectors, of which the Hancock inspirator is a type, and in which a single valve control distributes the steam and times the operation of lifter tubes, forcer tubes, and overflow valve. I therefore describe my improved valve in connection with such an injector.

In the drawings which illustrate my invention,-I+`igure l shows a boiler feeding` injector of the double tube type, in longitudinal section; and Fig. 2 shows on an enlarged scale, partly in side elevation and partly in section, a compound valve embodying my invention.

In Fig. 1 the compound valve is shown at V, N, N6, V and NG being the principal valve members while N generally designates the valve carrier. S is the valve controlling stem, and P a secondary valve, movable, though confined in, the carrier N of the compound valve. 1 represents the steam sup-` ply passage, 2 the water supply, E the lifter tubes and F the forcer tubes, of the inj ector. C and CAx are the seats, respectively, for the valve members i and V. C represents the casing generally. In injectors of this type as heretofore manufactured, the rear valve member of the compound steam valve has been seated over its port, as in the present valve, but the forward valve member has been a piston valve, fitting within a cylindrical port. The secondary valve, corresponding in function to the secondary valve I) of these drawings has heretofore not been completely satisfactory because it has been held to the valve stem by a one-sided engagement. Wear due to vibration has rendered the valve of this old style ilnperfect after varying periods of use, particularly at the forward end, where the piston valve is located. A full description of a valve of this character will be found in United States Patent No. 492,914 issued to William R. Park and myself on March 7, 1893.

Referring now to Fig. 2: N" represents generally the carrier for the compound valve, one member of which N6 is a flange integral with the carrier, the other member being the valve V, at the forward end of the carrier and slidingly mounted thereon, by means of the screw stem T, shouldered at T, threaded at T2 and swaged steam tight at V 1, said stem sliding in the bored-out head N1 of the carrier N. Valve member YG brings its seating face NT to bear on the seat C', which is formed in the casing, while valve member V brings its face V2 to bear on the seat C, also on the casing. IVhen valve member N6 is seated, steam pressure at the back of member V holds its face V2 to its seat C The forward end of the valve member V is, roughly speaking, conical in shape except for the narrow cylindrical portion V3 which fits loosely in the port formed b v the cylindrical opening in the casing at C4. The valve member V, as above stated, is susceptible of a limited sliding movement on the valve carrier N by reason of its manner of mounting which is as follows: The carrier N, which comprises sliding guide members NS, terminates in a cylindrically perforated head N10 situated at the juncture of the inclined converging arms N". A screw T, the cylindrical shank of which enters the bore of the head N10 with a free sliding fit, is screwed into a correspondingly threaded hole T2 in the valve member V, the shoulder T bringing up firmly against the rear side of the valve member V. The valve member V is rolled or swaged over the threaded portion of the screw T at V4 so that the valve member V is securely and inseparably joined to the valve carrier N, with freedom to slide within the limits permitted by the dimensions of the screw T and head N10.

JVhen the valve carrier N is moved forward the loosely mounted valve member V enters the port C4 and thereupon the steam pressure acting at the rear of the valve member V carries it toward and finally to a seat upon the seating surface C3 formed in the casing; this seating of the valve member V will therefore under normal conditions ust precede the seating of the valve member l G, which is positively brought to its seat at C by the forward movement of the stem S. By thus arranging the two valve members V and NG' so that within a suitable range their movements are mutually independent, the two valve members will seat accurately and tightly without reference to such changes in relative position of the valve seats as may be due to variations in temperature or un equal wear. Both valve members are, strictly speaking, seating valves as distinguished from piston valves, so that no reliance is placed upon the tting of a piston valve with .its aperture, a mode of closure which is peculiarly susceptible to deterioration in accuracy. The valve member Vcan sustain considerable wear without losing its capacity for accurate steam tight seating and can easily be reground to a seat, like any seating valve, whenever this may be found necessary.

In order to insure smoothness of action in the compound valve herein described, I have contrived and adopted the construction of the secondary valve P shown in Fig. 2. This secondary valve seats over the port opening L in the valve carrier N and controls this port and also the smaller ports provided with perforations N4 which are drilled radially through the side of the valve carrier N terminating in the annular recess N3. The secondary valve P is centrally recessed as P to receive the forward end of the stem S; this recess P lies at the bottom of a larger recess which is threaded to receive a threaded thimble Q. This threaded thimble Q is made to engage the stem S with a sliding fit. Near the forward end of the stem S an annular groove is formed at S,`this annular groove leaving the stem S with a disk-shaped head S2. The thimble Q is recessed at its forward end at Q to admit the divided ring R, the two parts of which fit fairly closely upon the reduced portion of the stem S, the outer diameter of the divided ring R, R being such that its two parts fit into the recess Q. In assembling the secondary valve P, first the cap M which is recessed at M is slipped over the stem S and'after it the thimble Q. The two portions R, R, forming the divided ring, vare then placed around the reduced part-of the stem S at S and the thimble Q slid forward so as to contain the divided ring R, R within the recess Q. Then the secondary valve P is screwed on to the thimble Q until the divided ring R, R is pinched between the thimble Q and the inner surface P2.of the secondary valve member P. This assemblage leaves the stem S2 in the recess P with very little play to move therein, enough however being preferably allowed so that the secondary valve P may not be too rigidly attached to the stem S. Finally, the cap M is screwed into the threaded end M of the valve carrier N, the flange l 2 of the said cap surrounding the rear end of the thimble Q. By this mode of assembly the thrust and pull of the stem S on the secondary valve P is evenly distributed and no opportunity is given for any chatter, which in constructions heretofore employed has taken place to such an extent as to wear the surfaces of the compound valve unduly. The secondary valve P slides with a fairly snug fit on the cylindrical inner surface l 2 of the rearward projection N of the valve carrier N, and comes to a seat on the surface N5.

The operation of the above described compound valve is in general, the same as that of the compound valves heretofore employed in boiler feeding injectors of the type represented by the Hancock inspirator. Initial rearward movement of the stern S lifts the secondary valve P from its seat N5 permitting steam to pass through the radial ports Nt, the central port L and thence to the appropriate steam tubes. Further movement of the stem S draws the secondary valve P still further back until the thimble Q brings up against the rear wall of the chamber formed by the hollow cylindrical end N of the carrier N and the casing cap M. Additional further movement starts valve member N6 from its seat to admit steam in greater volume than before into the space between the seating surfaces C and C3, the valve carrier N sliding in the bearing formed at C2. Finally, the forward end of the car rier N comes to a bearing upon the head of the screw T and lifts the valve member V from its seat at C3 to admit steam through the port at C4.

Since the. stem head S2 bears evenly around the divided ring R, the draft of the stem upon the secondary valve P and through it upon the valve carrier N is symmetrically distributed and applied so that the movement of all these parts is smooth and free from chatter whether the compound valve is being opened or closed. Consequently, the valve member V enters the port at G4 quietly and smoothly to 5nd its seat in advance of the seating of the valve member, as hereinabove described.

I claim:

1. The combination, with two relatively fixed valve seats, of a compound valve comprising a valve carrier, one valve member fixed with relation to the valve carrier, the other movably mounted on the valve carrier, and means to move the carrier toward and from the said valve seats, the two valve members adapted to seat on the respective relatively fixed valve seats.

2. The combination, with two relatively fixed valve seats, of a compound valve comprising a valve carrier, one valve member fixed with relation to the valve carrier, the other valve member provided with a stem, said stem mounted to slide in the valve carrier, and means to movethe carrier toward and from the said valve seats, the two valve members adapted to seat on the respective relatively fixed valve seats.

3. The combination, with two relatively fixed valve seats in axial alinement with each other, of a compound valve comprising a valve carrier, one valve member at the rear end of said carrier and fixed with relation thereto, another valve member at the forward end of' the carrier mounted in sliding` relation thereto with limited range of movement thereon, means to move the carrier toward and from the said valve seats, the two valve members adapted to seat on the respective relatively fixed valve seats.

4. In a compound valve, for seating over two relatively fixed ports, the combination of a valve carrier, two primary valves to cooperate with relatively fixed seats, one fixed with relation to the 'carrier and the other movably mounted on the valve carrier, and a secondary valve mounted and movable to a limited extent in the valve carrier, ports in said valve carrier controlled by the secondary valve, and means to move the secondary valve, and through the medium of the secondary valve to move the valve carrier and the primary valves.

5. In a compound valve, for seating over two relatively fixed ports, the combination of a valve carrier, two primary valves to cooperate with relatively fixed seats, one fixed with relation to the carrier and the other movably mounted on the valve carrier, a secondary valve mounted and movable to a limited extent in the valve carrier, ports in said valve carrier controlled by the secondary valve, said secondary valve comprising a cylindrical shell, threaded to receive a threaded thimble, and valve operating` means comprising the thimble, threaded into the secondary valve shell, a valve stem, annularly grooved, and a divided ring in said groove, clamped between the thimble and secondary valve shell.

Signed by me at Boston, Massachusetts, this twenty-fifth day of February, 1913.

BELVIN T. WILLISTON.

Witnesses:

ODIN ROBERTS, G. VRIGHT AnNoLn Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patent. Washington, 1). C." 

